The present invention relates to a solar heater.
At present a commercially available solar heater substantially comprises a frame in which there are arranged pipes through which the fluid, e.g. water, to be heated flows. Said pipes are usually made of a blackened material and the bottom of said frame also is made of a dark material whereas the upper plate has to be made of a transparent material. This system has a drawback in that the yield of the sun's rays is rather low.
It has therefore been desirable to provide a system by which the yield of the sun's rays is increased. However, such a system should also be substantially easy to manufacture and erect and should not be too expensive.
The present invnetion thus consists in a solar heater for heating a fluid which is constituted by a frame, a bottom plate, partitions, an upper plate made of a transparent material and an inlet and outlet for the fluid.
The invention will be illustrated with reference to the use of water, as this will most probably be the fluid used in Israel. However, in cold climates at first a low freezing fluid will be used which will then serve as a heat-exchange unit.
The bottom plate is preferably made of a blackened material, e.g. metal, plastic, etc. However, this is not always necessary as will be shown hereinafter.
The partitions are preferably connected to both plates and eventually also to one or more of the walls of the frame. Said partitions may have any desired suitable shape, i.e. they may be straight, oblique, curved, etc. Said partitions enable the fluid flowing through the device to remain for a long time within it and to absorb a large amount of heat. Moreover, they also may serve as connecting means of both plates.
Said partitions may extend in either horizontal or vertical direction.
The upper plate is made of any commercially available transparent material, e.g. glass, perspex, a suitable plastic material, e.g. P.V.C., etc.
It is easily understood that the area of water heated in accordance with the present invention is greatly increased by the method of the present invention.
Naturally there may be arranged more than one transparent plate the distance between the various transparent plates serving as insulation.
If desired the bottom or the upper plate may be made together with the partitions ans one piece which saves material and costs. In certain circumstances it may be possible to manufacture said device as one unit, i.e. the frame, the plates and the partitions by way of extrusion.
Sometimes it is desirable to add blackened metal plates between the partitions which plates are suitably arranged. In this case the lower plate must not be made of metal. It may for example be made of the same material of which the upper plate is made or from any other suitable material.
It is readily understood that it is advantageous to put around the entire device a good insulating material, e.g. a glass wool, foamed polystyrene, foamed polyurethane, etc.
The frame preferably comprises means which may be connected to each other so that several solar heaters according to the present invention may be connected to each other and thus form a part of a roof, a wall, etc.
The blacking is performed by methods known per se. One may use a dark fluid either as an addition to the blacking agent or instead of it.
In another aspect of this invention one may use a big concave mirror coated with a reflecting material and covered with a transparent plate into which a narrow unit of the solar heater according to the present invention is inserted in order to improve the efficiency of the sun's rays.
A narrow unit in connection with the present invention comprises preferably the bottom plate, advantageously made of a transparent material, the frame walls, partitions and optionally a metal plate inside the unit. The transparent plate covering the mirror, serves as the upper plate of the unit. However this modification of the invention is not restricted to this possibility and any other narrow unit described above and within the scope of the present invention may be utilised.
A preferred embodiment of said modification consists in a solar heater for directly heating a fluid supplied thereto comprising:
a concave member having a predetermined length with a reflective material disposed on an inner surface thereof;
a transparent plate having a predetermined width, an upper surface and a lower surface, said transparent plate being positioned on said concave member to form a closed container between the inner surface of said concave member and the lower surface of said transparent plate;
a bottom plate;
frame walls being operatively connected to said bottom plate and to said transparent plate for forming a fluid tight thin space;
partition plates extending between both said plates;
an inlet being operatively connected to said fluid tight thin space for supplying a fluid thereto;
an outlet being operatively connected to said fluid tight thin space for discharging a fluid therefrom;
said fluid tight thin space being operatively positioned within said closed container formed by said inner surface of said concave member and said lower surface of said transparent plate for direcly heating a fluid circulated through said inlet and discharged from said outlet by utilization of the rays of the sun.
In some embodiment said fluid tight thin space is in a position centrally disposed along the width of said transparent plate and centrally disposed with respect to said concave member.
Naturally also in this case there may be more than one transparent plate above the mirror.
The entire solar heater or parts thereof may be manufactured by way of extrusion.
All embodiments of the solar heater according to the present invention may be utilized as one unit or be erected in series. In the latter case the several units may be manufactured together with the support and thus form a part of a roof, of a wall or the like.